Flu season finally arrives, CDC reports

The flu season may finally be picking up steam after the slowest start in nearly three decades, a new government report suggests.

The Centers for Disease Control and Prevention reports an uptick in the number of samples testing positive for the virus -- 10.5 percent in the first week of February versus 7.6 percent the week before.

That suggests that the flu season is just off to a late start, CDC researchers say. Interestingly, it’s only the second time in 29 years that the percentage of respiratory samples testing positive remained under 10 percent through January.

"The peak of flu cases most commonly occurs in January or February, but the timing can vary significantly year to year," says Dr Otto Yang, professor of medicine, division of infectious diseases, at the David Geffen School of Medicine at the University of California, Los Angeles.

Flu season generally hits as early as October and can continue as late as May.

"It's difficult to predict if this will overall be lower than other years, because we have not yet reached the peak yet," Yang says.

Another of the CDC’s indicators that suggests that flu activity is starting to pick up in certain areas around the country is the count of people who show flu-like symptoms. Two regions -- Central and Northwestern U.S. -- are reporting a bump in influenza-like illnesses above baseline for the first time this year. And California is now reporting widespread influenza activity, while Missouri, Texas and Virginia have been reporting localized upticks.

Yang suggests the flu is peaking first in California because of its coastal location. "I can only speculate, but California is a state with lots of people traveling in and out, including people from areas where flu typically starts its spread each season," Yang says.

That may bode ill for the rest of the country, says Dr. Richard Zimmerman, a professor of family medicine at the University of Pittsburgh School of Medicine. “It’s fairly common for the west to precede the east,“ he explains. “But that’s not always true.”

If you still haven’t gotten your flu shot this year, get vaccinated right away, the CDC recommends, and Zimmerman agrees.

“This is really the last chance to get vaccinated,” he says. “It takes anywhere from one to two weeks for the vaccine to become effective.”

Other than vaccination, stay at home when you're sick -- and cross your fingers that your colleagues or schoolmates do the same, Zimmerman says. (Although for those who don’t have any sick leave left -- or never had any in the first place -- that can be a tough call.)

The only other protection you have against the flu is regular hand-washing. But no matter how fastidious you are, hand washing can only do so much in face of a virus that is mostly spread through the air when people cough and sneeze.